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United States Patent |
6,235,138
|
Parks
,   et al.
|
May 22, 2001
|
Polyurethane foam/PVC laminate for automotive instrument panels
Abstract
The present invention relates to a process for the production of a
polyurethane foam backed instrument panel. This process comprises slicing
a free-rise bun of polyurethane foam to form a skived polyurethane foam,
bonding the skived foam to a skin material to form a laminate, optionally,
rolling the foam/skin laminate, thermoforming the foam/skin laminate into
an instrument panel skin, positioning the instrument panel skin into the
cavity of a mold, positioning a retainer into the core of the mold,
adhering the retainer to the laminate by placing an adhesive film onto the
retainer, closing the mold to apply heat and pressure, and removing the
resultant instrument panel from the mold. Suitable polyurethane foams for
the present invention may be flexible foams or semi-rigid foams. This
invention also relates to the polyurethane foam backed instrument panels
produced by this process.
Inventors:
|
Parks; Kristen L. (Bayer Corporation 100 Bayer Rd., Pittsburgh, PA 15205-9741);
Milliren; Charles M. (Bayer Corporation 100 Bayer Rd., Pittsburgh, PA 15205-9741)
|
Appl. No.:
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301675 |
Filed:
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April 28, 1999 |
Current U.S. Class: |
156/214; 156/212; 156/222; 156/224; 156/255; 156/256 |
Intern'l Class: |
B32B 005/18; B32B 031/20; B32B 027/40 |
Field of Search: |
156/77,78,212,214,221,222,224,303.1,250,255,256
|
References Cited
U.S. Patent Documents
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|
4504536 | Mar., 1985 | Wong.
| |
4769278 | Sep., 1988 | Kamimura et al. | 428/282.
|
4902362 | Feb., 1990 | Stewart et al. | 156/79.
|
4910067 | Mar., 1990 | O'Neill.
| |
4941936 | Jul., 1990 | Wilkinson et al. | 156/274.
|
5256236 | Oct., 1993 | Woller | 156/290.
|
5372379 | Dec., 1994 | Parker | 280/728.
|
5380785 | Jan., 1995 | Ngoc et al.
| |
5395580 | Mar., 1995 | Morita et al.
| |
5407225 | Apr., 1995 | Cooper.
| |
5409649 | Apr., 1995 | Pool | 264/51.
|
5415940 | May., 1995 | Ngoc et al.
| |
5445208 | Aug., 1995 | Shaner et al.
| |
5503927 | Apr., 1996 | Ragland et al.
| |
5536351 | Jul., 1996 | Rheinlander et al. | 156/212.
|
5554252 | Sep., 1996 | Foran | 156/497.
|
5565259 | Oct., 1996 | Juriga | 428/138.
|
5616396 | Apr., 1997 | Ueki et al.
| |
5633063 | May., 1997 | Lause et al.
| |
5677048 | Oct., 1997 | Pushaw.
| |
5750263 | May., 1998 | Ngoc et al.
| |
5759324 | Jun., 1998 | Roth et al.
| |
5783016 | Jul., 1998 | Gallagher et al. | 156/214.
|
5851338 | Dec., 1998 | Pushaw.
| |
Other References
K.L. Parks, P. Gansen, J.R. Gricar & U. Liman, "New Developments in
Polyurethane Foam Systems for Automotive Instrument Panels", (date
unavailable).
|
Primary Examiner: Yao; Sam Chuan
Attorney, Agent or Firm: Gil; Joseph C., Brown; N. Denise
Claims
What is claimed is:
1. A process for the production of a polyurethane foam backed instrument
panel comprising:
A) slicing a free-rise bun of polyurethane foam to form a skived
polyurethane foam,
B) bonding the skived polyurethane foam to a skin material to form a
laminate,
C) optionally, rolling the foam/skin laminated product from B),
D) thermoforming the foam/skin laminate into an instrument panel skin,
E) positioning the instrument panel skin into the cavity of an instrument
panel mold,
F) positioning an instrument panel retainer into the core of the instrument
panel mold,
G) adhering the instrument panel retainer to the foam/skin laminate,
H) closing the mold to apply heat and pressure, and
I) removing the resultant instrument panel from the mold.
2. The process of claim 1, wherein said polyurethane foam is a semi-rigid
foam or a flexible foam.
3. The process of claim 1, wherein said skin material is selected from the
group consisting of polyvinyl chloride, polyurethane, acrylonitrile
butadiene styrene/polyvinyl chloride alloys and thermoplastic olefins.
4. The process of claim 1, wherein said thermoforming occurs at
temperatures of about 90.degree. C. or less for less than about 1 minute
under moderate pressure.
5. The process of claim 1, wherein the instrument panel retainer is adhered
to the foam/skin laminate by placing an adhesive film onto the instrument
panel skin.
6. The process of claim 5, wherein the adhesive film is selected from the
group consisting of polyurethane adhesives and epoxy adhesives.
7. The process of claim 1, wherein the skived polyurethane foam has a
thickness of from about 5 to about 10 mm.
8. The process of claim 1, wherein the instrument panel retainer comprises
an injection-molded thermoplastic.
Description
BACKGROUND OF THE INVENTION
This invention relates to polyurethane foam/PVC (polyvinyl chloride)
laminates for automotive instrument panels, and to a process for the
production of these automotive instrument panels.
Automotive instrument panels are typically assessed for commercial
applications in terms of their ability to satisfy certain requirements
including, for example, colorfastness of the skin material after ageing,
adhesion properties, fogging characteristics, physical properties,
processability, etc. The use of semi-rigid polyurethane foam systems in
automotive instrument panels is discussed in the paper entitled "New
Developments in Polyurethane Foam Systems for Automotive Instrument
Panels" by K. L. Parks, P. Gansen, J. R. Gricar and U. Liman, Society of
the Plastics Industry, Proceedings of the Polyurethanes International
Technical Conference and Exposition (1996). This paper describes the
typical processes and materials that are used in instrument panel
manufacturing. Included are descriptions of new instrument panel
polyurethane foam systems with improved ageing performance.
Laminated artificial leather and a method of preparing it are disclosed in
U.S. Pat. No. 4,504,536. This polyvinyl chloride (PVC) laminated
artificial leather has an unfoamed polymeric resin outer layer, a foamed
polyvinyl chloride bottom layer having an abraded outer surface and at
least one intermediate layer comprising a fabric free polyvinyl chloride
between the facing surfaces of the outer and bottom layers, with the outer
layer being embossed on the outer surface to provide a leather appearance.
U.S. Pat. No. 4,769,278 describes resilient multi-layered members
comprising a surface skin layer, formed of PVC resin powder in gel form,
the outer side; a foam material layer, formed from foamed PVC resin
powder, the outer side of which is adhered to the inner side of the
surface skin layer; a cushion material layer, the outer side of which is
adhered to the under side of the foam material layer; and a stiff core
material layer on its inside side, the outer side of which is adhered to
the inner side of the cushion material layer.
Thermoplastic foam core, fiber reinforced resin structural composite
materials are described by U.S. Pat. No. 4,910,067. These structural
composite materials comprise a thermoplastic layer, a layer of fibrous
material spaced from the thermoplastic layer and a foam core disposed in
the space between the thermoplastic layer and the fibrous material. The
layer of fibrous material includes a resin impregnating this material and
holding the layer of fibrous material together to form a fiber reinforced
resin structure. Boats can be made from these structural composites.
U.S. Pat. Nos. 5,395,580, 5,407,225, 5,445,208 and 5,616,396 describe
methods of producing automotive interior components, including door trim,
door panels and airbag doors. The automotive interior components of U.S.
Pat. No. 5,395,580 are laminated structures comprising a surface skin
layer having an attractive appearance and feel, and a rigid core member
comprising a synthetic resin. Door trim is one example of the types of
automotive interior components which may be prepared from this method.
U.S. Pat. No. 5,407,225 describes an invisible airbag door having a
reinforced polyvinyl chloride shell. The invisible door arrangement of the
airbag is covered by the decorative instrument panel and comprises a
curved substrate or insert that is molded of relatively rigid plastic
material and secured in the passenger compartment behind the instrument
panel and in front of the canister containing a deflated airbag. The
substrate has an integral, rectangular frame which projects inward toward
the canister and defines a rectangular opening for deployment of the
airbag when inflated. This invisible door arrangement further comprises
two similar sheet metal doors that close the opening outlined by the face
and cooperate to create an opening through the instrument panel upon
deployment of the airbag. The doors are made of one-piece construction and
preferably of aluminum. The PVC shell is reinforced with a urethane
adhesive coating that is flexible.
U.S. Pat. No. 5,445,208 discloses vinyl door panel sections and a method of
making door panel sections, specifically garage door panels. These door
panel sections comprise a rectangular door panel section having a front
skin, a rear skin, opposing top and bottom portions and first and second
sides. The door panel section includes a first sheet member and a second
sheet member. The first sheet member is a polyvinylchloride material and
has outer and inner surfaces, and top and bottom sections. The second
sheet member is a non-metallic material and has outer and inner surfaces,
and top and bottom sections. The front skin of the panel is comprised
essentially of the first sheet member, and the rear skin of the panel
section is comprised essentially of the second sheet member. The rigid
foamed core is bonded to the inner surface of the first sheet member and
is enclosed between the front and rear skins for unitizing the panel
section.
Laminated building panels and a method for their production are disclosed
by U.S. Pat. No. 5,633,063. These comprise plastic facing sheets on one or
both faces of a rigid foam core with fibrous glass fiber mat material
mechanically connecting the facing sheet to the core. The facing sheets
are formed of suitable thermoplastic polymers including polyvinyl
chloride, polyolefins, polycarbonates, acrylics, etc. These building
panels are formed by extruding a molten polymer through an extrusion die
to form a polymer layer, positioning the glass fiber mat adjacent to the
polymer layer, and compressing the polymer layer and mat together before
the polymer layer has solidified so that portions of the glass mat are
embedded in the polymer and portions of the mat project from the polymer
layer. Embossing rollers can be used to compress and emboss the polymer
layer. The assembled facing sheet is solidified by cooling. Inner facing
sheets are made in a similar manner, except the glass mats are preferably
applied to both sides or faces of the polymer layer so that glass fibers
project from both faces of the sheet.
Automotive door trim components comprise a main body integrally combining a
resin core member and a surface skin member by a mold press forming
process and an attachment member attached to a part of the main body. The
attachment member is attached to the main body by way of connecting parts
of the resin core member still at least in a semi-molten state due to the
mold press forming process. The connecting part eventually solidifies so
as to achieve a secure engagement between the resin core member and the
attachment member.
U.S. Pat. No. 5,759,324 provides a process for binding a cover to a shaped
padding, which specifically comprises polyurethane foam. Seat cushions can
be produced by this process. This process comprises arranging a cover in a
cold-shaping device and fixing it there by means of a holding frame. Then,
an adhesive is placed on the internal walls of the cover and subsequently
heated to a high temperature with the surface of the padding intended to
cooperate with the internal walls of the cover. The heating is interrupted
once a predetermined temperature is reached and the heated foam padding is
immediately applied to the internal walls of the cover coated with the
adhesive, leading to rapid setting of the adhesive. The cold-shaping
device is then opened and the padding with its cover is removed.
Pressure sensitive adhesive laminates and methods of producing these are
disclosed by U.S. Pat. No. 5,503,927. These laminates comprise a polymeric
layer having an active surface, a coating of a curable urethane primary on
the surface and a pressure sensitive adhesive applied to the coated
surface. The method of forming these laminates comprises applying to the
active surface of the polymeric layer a coating of a curable urethane
primer, then applying to the coated surface a layer of pressure sensitive
adhesive. Laminates are also formed comprising a polymeric layer and a
curable urethane primer comprising casting a liquid polymer on a sheet of
curable urethane primer in the form of a film and allowing the polymer to
cure to form the polymeric layer on the urethane film or sheet.
U.S. Pat. Nos. 5,380,785, 5,415,940 and 5,750,263 describe low fogging
rubbery polymers and their utilization in automotive interiors. These
rubbery compounds can be blended with polyvinyl chloride to make leathery
compositions having good heat and ultraviolet light resistance, and low
fogging characteristics. The automotive panels are comprised of a
semi-rigid urethane foam which is supported by a rigid backing, and the
semi-rigid foam is covered with a leathery skin.
The primary disadvantage of previously known processes is that it is
necessary to mold the polyurethane foam directly onto the retainer and
skin materials. Polyurethane foam-backed instrument panels are typically
produced by positioning a skin material in the cavity of an IP (instrument
panel) tool, positioning the plastic retainer in the core, pouring the
polyurethane foam onto the skin, closing the tool, applying heat and
pressure, and finally opening the tool to remove the IP pad for assembly.
The disadvantage that is inherent in this process is that any foam defects
that result from the molding process result in scrapping the skin
material, the retainer, and the polyurethane foam. Instrument panels are
large parts that are difficult to foam consistently without voids.
Processing of these parts is influenced by a myriad of factors including
tool temperature (hot and cold spots plus day-to-day variations), seasonal
variations including humidity level, and timing of the closing of the mold
in relation to the foaming reaction, etc. Foam voids are difficult and
expensive to repair. The ability to produce an instrument panel using a
skin-backed laminate would provide a method to produce instrument panels
without foam defects and therefore, a low-cost manufacturing method.
SUMMARY OF THE INVENTION
This invention relates to polyurethane foam/PVC laminate instrument panels
and to a process for the production of these polyurethane foam/PVC
laminate instrument panels. These polyurethane foam/PVC laminates provide
a low cost alternative to the polyurethane foam/PVC instrument panels
produced by the open-pour method previously described. In addition, the
polyurethane foam can be made to feel softer than polypropylene foam that
may be used for the same purpose and has the capability to provide
improved adhesion to the PVC skin material.
The process for the production of a polyurethane foam backed instrument
panel comprises the steps of:
A) slicing a free-rise bun of polyurethane foam to form a skived
polyurethane foam,
B) bonding the skived polyurethane foam to a skin material to form a
laminate,
C) optionally, rolling the foam/skin laminated product formed in B) for
storage purposes,
D) thermoforming the foam/skin laminate into an instrument panel skin,
E) positioning the instrument panel skin into the cavity of an instrument
panel mold,
F) positioning an instrument panel retainer into the core of the instrument
panel mold,
G) adhering the instrument panel retainer to the foam/skin laminate by, for
example, placing an adhesive film onto the instrument panel skin or other
suitable means,
H) closing the mold to apply heat and pressure, and
I) removing the resultant instrument panel from the mold.
The present invention also relates to the resultant polyurethane foam
backed instrument panels produced by the above process.
DETAILED DESCRIPTION OF THE INVENTION
Suitable free-rise buns of polyurethane foams for the present invention
include, for example, polyurethane foams that are either semi-rigid or
flexible, and may be prepared by the reaction of a suitable di- or
poly-isocyanate component with an isocyanate-reactive component in the
presence of a suitable blowing agent and one or more catalysts. Suitable
di- and/or poly-isocyanates include aromatic isocyanate compounds such as,
for example, polymethylene poly(phenyl isocyanate), toluene diisocyanate,
naphthylene diisocyanate, etc. Suitable isocyanate-reactive compounds to
be used in the present invention include, for example, polyether polyols,
polyester polyols, amine-terminated polyether polyols, polythioethers,
polyacetals, polycarbonates, etc., which typically contain from 2 to 6
isocyanate-reactive groups of the type known for the production of
polyurethanes. Compounds such as these generally are characterized by a
molecular weight of from about 62 to about 6,000, preferably from about
2,500 to about 6,000, and more preferably from about 4,000 to about 6,000;
and have an OH number of from about 20 to about 2,000, preferably from
about 25 to about 2,000, and more preferably from about 28 to about 2,000.
Blowing agents which are suitable for the preparation of the free-rise
buns of polyurethane foams include, for example, water and/or readily
volative organic substances. Some examples of suitable organic blowing
agents include compounds such as acetone, ethyl acetate, halogen
substituted alkanes such as, for example, methylene chloride, chloroform,
ethylidene chloride, vinylidene chloride, monofluorotrichloromethane,
chlorodifluoromethane as well as butane, hexane, heptane and diethyl
ether. Azo compounds such as azoisobutyric acid nitrile are also suitable.
The free-rise bun of polyurethane foam is sliced by an electric saw to form
a skived polyurethane foam. These slices of skived polyurethane foam may
vary in thickness from about 5 to about 10 mm.
The skived foam is bonded to a skin material to form a laminate. Bonding
can be achieved by applying an adhesive film to the skin material and
adhering the skived foam on top of the adhesive film, using heat and
pressure in a continuous process such as, for example, a laminator. Some
examples of skin materials that the skived polyurethane foam may be bonded
to include thermoformable skin materials such as, for example, polyvinyl
chloride (PVC), polyurethane, acrylonitrile butadiene styrene (ABS)/PVC
alloys, thermoplastic olefins (TPO's), etc. The preferred method of
bonding the skived foam to the skin material is by use of a laminator.
Polyvinyl chloride is a preferred skin material. Suitable laminates for
the process of the present invention must exhibit satisfactory adhesion
and be free of defects.
Once the laminate is formed, it is optionally rolled up and stored. In an
alternate embodiment, the formed laminate is used immediately and step C)
is omitted from the process. In the embodiment where the formed laminate
is rolled up and stored, at some later time, the roll of foam/skin
laminate is unrolled, cut to the desired length, and thermoformed into an
instrument panel skin by placing the skin-side of the laminate onto the
cavity of the skin-forming tool. Thermoforming occurs at temperatures of
about 90.degree. C. or less, preferably for less than about 1 minute using
moderate pressure.
The IP-shaped skin is then placed skin-side down in an IP tool or mold and
bonded to the IP retainer. An instrument panel retainer is positioned into
the core of the instrument panel mold and is attached to the foam/skin
laminate by placing an adhesive film onto the laminate. Suitable adhesive
films include, for example, polyurethanes and epoxies. Instrument panel
retainers serve to mount the instrument panel to the car frame, and are
the structural parts. Retainers are typically made of injection-molded
thermoplastics.
The following examples further illustrate details for the process of this
invention. The invention, which is set forth in the foregoing disclosure,
is not to be limited either in spirit or scope by these examples. Those
skilled in the art will readily understand that known variations of the
conditions of the following procedures can be used. Unless otherwise
noted, all temperatures are degrees Celsius and all parts and percentages
are parts by weight and percentages by weight, respectively.
EXAMPLES
The process of the present invention could be practiced by following the
example set forth below.
A polyurethane foam free-rise bun is skived to a 10 mm thickness. The foam
is then adhered to a PVC sheet using a conventional laminator. The
polyurethane foam/PVC laminate is then thermoformed into the shape of a
PVC skin. The shaped laminate is then placed into the cavity of an IP
tool.
A thermoplastic retainer is then placed into the core of the same IP tool.
An adhesive film is then placed on the laminate. The IP tool is then
closed. heat and pressure are used to bond the laminate to the retainer.
The laminate/retainer assembly is then removed from the mold, inspected
and trimmed.
Although the invention has been described in detail in the foregoing for
the purpose of illustration, it is to be understood that such detail is
solely for that purpose and that variations can be made therein by those
skilled in the art without departing from the spirit and scope of the
invention except as it may be limited by the claims.
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